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Nobel Prize for Magnetic Sandwiches

Our world has become digitalized. In the global village, data highways are replacing sidewalks and computer servers are simultaneously serving as the intersections and warehouses in which our data packages are waiting to be dispatched.

The discovery of the giant magnetoresistance (GMR) revolutionized computer hardware.

The key prerequisite for millions of users being able to easily access their data from any place in the world, whether email messages, video clips or huge databases, is the enormous storage capacity of today's hard drives. A physical effect – discovered in the labs of Forschungszentrum Jülich – has helped make hard drives in this power class possible.

Back in the 1980s, Peter Grünberg studied metallic layers at Jülich that were several millimetres long and wide, but no more than a few atomic layers thick. In the specimens, a non-magnetic chromium layer lies between two magnetic iron layers, forming a nanometre-thick sandwich that is highly sensitive to external magnetic fields. The total electrical resistance of the sandwich changes very strongly, even when the magnetic environment changes only slightly. The giant magnetoresistance effect (GMR) is named for this behaviour.

In this way, the magnetic storage units for the individual bits on the hard drive can be read out very easily and further reduced in size, so that the enormous storage capacities needed today can be maintained. In a matter of 10 years, the GMR effect managed the leap from discovery and patenting to industrial mass production and is thus a prime example of rapid translation of basic research into application and a million-euro market.

For his discovery, which has had such a profound impact on our modern world, Peter Grünberg was awarded numerous prizes and distinctions, including the German Future Prize for Technology and Innovation in 1998 and the Nobel Prize for Physics in 2007.